A power transmitting apparatus is known in the art, for example, as disclosed in International Patent Publication No. WO2009/010819 (corresponding to Patent Application Publication No. US2010/0184549 A1). The power transmitting apparatus has a planetary gear device for transmitting rotational force among a driving shaft for connecting an internal combustion engine to driving wheels, a flywheel for accumulating rotational energy, and an electric power generator. More in detail, the planetary gear device provided in the power transmitting apparatus has a sun gear, a carrier and a ring gear, which are respectively connected to the flywheel, the driving shaft and the electric power generator. According to the power transmitting apparatus, kinetic energy of a vehicle can be transmitted to the flywheel via the driving shaft and the planetary gear device and a regeneration control for accumulating the kinetic energy in the flywheel can be carried out.
According to the power transmitting apparatus of the above Patent Publication, the rotational energy accumulated in the flywheel may be discharged via the sun gear of the planetary gear device depending on an operational mode of the electric power generator, even when the rotational energy was once accumulated in the flywheel.
Not only in the power transmitting apparatus having the flywheel for accumulating the rotational energy but also in a power transmitting apparatus having any other energy accumulating device, this kind of unfavorable situation, which is caused by torque transmission from the energy accumulating device to a rotating device connected to the planetary gear device, may occur.